Lumen sterilization device and method

ABSTRACT

Devices and methods for sterilizing lumens involve a booster that is attached to the lumen. In preferred embodiments, the contact area between the lumen and the booster enhances the penetration of an antimicrobial agent to the contact area.

RELATED APPLICATION INFORMATION

This application is a continuation-in-part of U.S. application Ser. No.09/746,990, filed Dec. 22, 2000, which is a continuation-in-part of U.S.application Ser. No. 09/384,761, filed Aug. 27, 1999, now U.S. Pat. No.6,187,265; which is a continuation of U.S. application Ser. No.08/992,131, filed Dec. 17, 1997, now abandoned, all of which are herebyincorporated by reference in their entireties. This application is alsoa continuation-in-part of U.S. application Ser. No. 09,472,319, filedDec. 23, 1999, which is a continuation-in-part of U.S. application Ser.No. 08/915,922, filed Aug. 21, 1997, now U.S. Pat. No. 6,066,294, all ofwhich are hereby incorporated by reference in their entireties.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to the sterilization of medical devices. Inparticular, this invention relates to systems, methods and devices forsterilizing lumens.

2. Description of the Related Art

Articles such as medical instruments are normally sterilized before use.There are many methods of sterilizing medical equipment, including heattreatment and chemical methods. Heat sterilization is normally performedwith steam. Some equipment cannot withstand either the heat or themoisture from steam treatment. As a result, chemical sterilization isnow commonly used.

Chemical sterilization uses a sterilizing fluid such as hydrogenperoxide, ethylene oxide, chlorine dioxide, peracetic acid,formaldehyde, or a combination thereof. A plasma may be induced toenhance the sterilization process. Although chemical sterilization isnormally highly effective, it may not be as effective with medicaldevices having long, narrow tubes, or lumens. It is difficult for thesterilizing agent to completely penetrate and sterilize these longnarrow tubes. In order to enhance the penetration of the sterilizingagent down the entire length of the lumen, several methods and severalforms of apparatus have been developed to flow sterilizing agent throughthe length of the lumen, enhancing the effectiveness of the sterilizingtreatment.

For example, U.S. Pat. Nos. 4,410,492 and 4,337,223 describe anapparatus and a method for sterilizing lumens in which the lumen isplaced in a socket connected to a circulating pump. The pump circulatesthe sterilizing gas through the lumen. Although the method is effectivein sterilizing the lumen, the commercial apparatus uses ethylene oxideas a sterilant, and sterilization requires times of about 2-3 hours.Ethylene oxide is toxic. Additional aeration time is needed to removethe residual.

U.S. Pat. No. 5,580,530 describes a method for delivering sterilizingagent through long, narrow lumens. The lumen is inserted into an adaptorconnected to a vessel containing hydrogen peroxide. The vessel is calleda booster. The lumen, adaptor, and booster are placed in a sterilizationchamber. When the sterilization chamber is evacuated during thesterilization procedure, the hydrogen peroxide in the booster vaporizesand passes through the lumen, sterilizing the interior of the lumen.

An apparatus and a method for delivering sterilizing agent directly intolong, narrow lumens is described in U.S. Pat. Nos. 4,943,414, 5,580,530and 5,733,503. The lumen is inserted into an adaptor connected to asmall vessel containing hydrogen peroxide. The adaptor and the vesselwhich contains the hydrogen peroxide are called the booster. The lumen,vessel, and adaptor are placed into a sterilization chamber. When thesterilization chamber is evacuated, the hydrogen peroxide vaporizes andpasses through the lumen, providing the necessary hydrogen peroxide tothe interior of the lumen. Although effective, the method has somedisadvantages. First, in some forms of the apparatus, the booster mustbe “activated” manually by piercing a septum to make the hydrogenperoxide liquid accessible. Second, the booster is used only once beforeit is discarded. Third, the product has a limited shelf life. Thestorage and shipping conditions may affect the shelf life of theproduct.

In each of these sterilization methods, the lumen is held by aconnecting device, a socket in the case of U.S. Pat. Nos. 4,410,492 and4,337,223 or a truncated cone adaptor when using the method of U.S. Pat.No. 5,580,530. In all of these methods, there are areas of contactbetween the device and the lumen in the area where the lumen attaches tothe connecting device. It is difficult for the sterilizing agent topenetrate into these contact areas. There is a need for an apparatus anda method of enhancing the penetration of sterilizing gas or vapor intothese contact areas more effectively to allay any potential concernsabout incomplete sterilization.

There are also contact areas between the parts of medical devices havingtwo or more pieces. It is difficult to sterilize the contact areasbetween the parts which make up the medical device. There is a need fora method and an apparatus for enhancing the penetration of sterilantinto the contact areas between the pieces which make up the medicaldevice.

There is also a need for a method of sterilizing lumens which does notrequire the use of a booster with limited shelf life. Further, there isa need for a method which utilizes an apparatus which is reusable, toreduce costs.

SUMMARY OF THE INVENTION

In accordance with one aspect of the invention, an apparatus forsterilizing a lumen comprises a booster and a connecting device betweenthe booster and the lumen, wherein the connecting device comprises asilicone material. Preferably, the connecting device comprises texturedor uneven surfaces. In alternative preferred embodiments, the boostercomprises a vessel containing an antimicrobial fluid, or the booster isa dry booster.

In accordance with another aspect of the invention, an apparatus forsterilizing a lumen comprises a dry booster and a connecting devicebetween the dry booster and the lumen, wherein the lumen contacts theconnecting device at a contact area and wherein the contact area isadapted to enhance penetration of an antimicrobial vapor or gas to thecontact area. Preferably, the connecting device is constructed from amaterial, at least in the contact area, that is permeable to theantimicrobial vapor or gas, and/or the surface of the connecting devicein the contact area is textured or uneven. Preferably, the dry boosterencloses an internal volume that is greater than the internal volume ofthe lumen. Preferably, the dry booster comprises a flow restrictorand/or a check valve.

In accordance with another aspect of the invention, a system forsterilizing a lumen comprises: a vacuum chamber; a pump to evacuate thechamber; a dry booster attachable to and detachable from a lumen; and asource of germicide. Preferably, the dry booster comprises an adaptorthat contacts the lumen in a contact area; more preferably, the adaptoris constructed from a material, at least in the contact area, that ispermeable to a germicide. Preferably, the adaptor comprises a surfacethat is textured or uneven in the contact area. Preferably, the drybooster encloses an internal volume that is greater than the internalvolume of the lumen. Preferably, the dry booster comprises a flowrestrictor and/or a check valve.

In accordance with another aspect of the invention, a method forsterilizing a lumen comprises providing a dry booster, a connectingdevice, and a lumen; connecting a first end of the lumen to the drybooster with the connecting device, wherein the lumen contacts theconnecting device at a contact area; placing the dry booster, theconnecting device, and the lumen into a chamber, wherein the chamber isat a pressure; introducing an antimicrobial vapor or gas into thechamber; causing the antimicrobial vapor or gas to penetrate the contactarea and the lumen; and sterilizing the lumen. Preferably, theconnecting device, at least in the contact area, is permeable to agermicide, and/or the surface of the connecting device in the contactarea is textured or uneven. Preferably, the dry booster encloses aninternal volume that is greater than the internal volume of the lumen.In one embodiment, the method further comprises reducing the pressure inthe chamber, thereby at least partially evacuating the dry booster. Inanother embodiment, the method further comprises creating a higherpressure outside the dry booster than inside the dry booster; andflowing the antimicrobial vapor or gas from the chamber into the drybooster through the lumen. In another embodiment, the method furthercomprises reducing the pressure in the chamber after the flowing of theantimicrobial vapor or gas from the chamber into the dry booster throughthe lumen, thereby causing at least a portion of the antimicrobial vaporor gas in the dry booster to flow from the dry booster through the lumenand into the chamber.

In accordance with another aspect of the invention, an apparatus forsterilizing a lumen comprises a booster and a connecting device betweenthe booster and the lumen, wherein the lumen contacts the connectingdevice at a contact area and wherein the connecting device comprises anuneven or textured surface in the contact area. Preferably, theconnecting device is constructed from a material, at least in thecontact area, that is permeable to the antimicrobial vapor or gas. Inalternative preferred embodiments, the booster comprises a vesselcontaining an antimicrobial fluid, or the booster is a dry booster.

These and other embodiments are described in greater detail below.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective drawing of an assembled booster and adaptor witha lumen inserted in the opening of the adaptor;

FIG. 2 is an exploded perspective drawing of the booster, adaptor, andlumen of FIG. 1;

FIG. 3A is a sectional view of the adaptor and lumen, showing how thelumen fits into the opening of the adaptor;

FIG. 3B is a sectional view of the adaptor and lumen, with the lumeninserted into the opening of the adaptor;

FIG. 4 is a blow-up of FIG. 3B showing a sectional view of the area ofcontact between the adaptor and the lumen, where the flow of sterilantvapor through the textured area of the adaptor and through the materialof the adaptor is shown with arrows;

FIG. 5 is a schematic drawing of a pair of scissors having contact areasbetween the two parts of the scissors;

FIG. 6A is a sectional view of the contact area of the scissors of FIG.5 with the scissors in a closed position, where one of the pieces makingup the scissors is textured, according to an embodiment of theinvention;

FIG. 6B is a sectional view of the contact area of the scissors of FIG.5 with the scissors in an open position, where one of the pieces makingup the scissors is textured, according to an embodiment of theinvention;

FIG. 7 is a schematic drawing of a pair of scissors having contact areasbetween the two parts of the scissors;

FIG. 8A is a sectional view of the contact area of the scissors of FIG.7 with the scissors in a closed position, where both pieces of thescissors are textured, according to an embodiment of the invention;

FIG. 8B is a sectional view of the contact area of the scissors of FIG.7 with the scissors in an open position, where both pieces of thescissors are textured, according to an embodiment of the invention;

FIG. 8C is a sectional view of the contact area of the scissors of FIG.7 with the scissors in a closed position, where both pieces of thescissors are textured, according to an embodiment of the invention;

FIG. 8D is a sectional view of the contact area of the scissors of FIG.7 in an open position, where both pieces of the scissors are textured,according to an embodiment of the invention;

FIG. 9 is a perspective view of a contact area between two parts of amedical device, where both parts are textured and where the two partsare in a closed position;

FIG. 10 is a perspective view of a contact area between two parts of amedical device, where both parts are textured and where the two partsare in an open position;

FIG. 11 is a schematic drawing of a pair of scissors having contactareas between the two parts of the scissors;

FIG. 12A is a perspective view of texturing according to an embodimentof the invention, where the texturing is in the form of projectionsplaced randomly on the contact surface;

FIG. 12B is a perspective view texturing according to an embodiment ofthe invention, where the texturing is in the form of projections placedin rows on the contact surface; and

FIG. 12C is a perspective view of texturing according to an embodimentof the invention, where the texturing is in the form of grooves.

FIG. 13 is a schematic diagram of a lumen attached to an adaptor whichis connected to a vessel according to a preferred embodiment of theinvention.

FIG. 14 is a schematic diagram of a lumen attached to an adaptor whichis connected to a flow restrictor and a vessel according to a preferredembodiment of the invention, where the vessel has a check valve.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The embodiments of the method and the apparatus of the present inventionrelate to the sterilization, disinfection, rinsing, drying, or cleaningof articles such as medical instruments having contact surfaces.Although certain embodiments of the apparatus and the method arediscussed with the example of sterilizing areas of contact between alumen and an adaptor, the apparatus and the method have broadapplicability to a variety of forms of apparatus and methods. Forexample, the embodiments of the apparatus and the method of the presentinvention can be applied to disinfection, rinsing, or cleaning as wellas sterilization.

The embodiments of the method and the apparatus apply to any situationin which there are contact areas between an article to be sterilized,disinfected, rinsed, dried, or cleaned and a device, part, adaptor,external housing, or connector. The embodiments of the method and theapparatus also apply to medical devices having two or more parts, wherethere are points of contact between the two parts. The embodiments ofthe method and the apparatus can be applied wherever contact areas existon a device. The terms “sterilize”, “sterilant”, and other forms of thisword throughout the specification and claims are to be construed broadlyand are to be understood to include disinfection and other antimicrobialprocesses.

Embodiments of the method and the apparatus of the present invention areapplicable to, for example, sterilization, rinsing, disinfection,drying, or cleaning of lumens or medical instruments having one or morelumens. The term “instruments having one or more lumens” as used hereinapplies to medical or surgical devices such as endoscopes, catheters,tubing, or similar instruments or articles having one or more internallumens. In this embodiment of the device and the method of the presentinvention, antimicrobial fluid may be supplied directly to the lumen orinterior of the tube of the instrument during the sterilization process.In general, the lumen is held by an adaptor which is connected to asource of antimicrobial agent or germicide. There are contact surfacesbetween the adaptor and the lumen.

To enhance the sterilization, rinsing, disinfection, or cleaning of thecontact surfaces, one or a combination of the following properties maybe utilized in the adaptor, medical device, or connector design andmaterial selection: first, applying texture or uneven surfaces to thecontact area so as to reduce surface contact and enhance axial diffusionof sterilant; second, constructing the adaptor, medical device, orconnector, at least in the contact area, from a material which hasminimal chemical and physical interaction with the sterilant; and third,using a material of construction, at least in the contact area, which ispermeable to the sterilant so that the sterilizing agent can penetratethe material, enhancing radial diffusion of the sterilant.

The texture or uneven surfaces are designed so that more sterilant,disinfectant, rinsing fluid, or cleaning fluid can flow around thetextured or the uneven surfaces on the adaptor or connector than flowsthough the material of the adaptor or connector.

FIGS. 1 and 2 illustrate an embodiment of an apparatus suitable for usein an embodiment of sterilizing or disinfecting a lumen. FIG. 1 showsthe assembled apparatus, and FIG. 2 is an exploded view, showing thevarious parts of the apparatus. A booster 20 is attached to an adaptor30. A lumen 50 is inserted into an opening 32 of the adaptor 30. Theopening 32 is normally of slightly smaller diameter than the outerdiameter of the lumen 50 so that there is a snug fit between the insideof the opening 32 and the outside of the lumen 50.

Two forms of the booster 20 are described in detail in col. 9 line 11 tocol. 12, line 19 and FIGS. 5 to 13 of U.S. Pat. No. 5,580,530, herebyincorporated herein by reference in its entirety. Briefly, the booster20 includes a vessel for containing hydrogen peroxide, a membrane wallcapping the vessel containing the hydrogen peroxide, and an opener witha hollow spike which is used to breach the membrane wall, activating thebooster so that the hydrogen peroxide can escape from the vessel. Oneform of the booster is shown as 100 on FIGS. 5 to 9 and an alternativeform as 200 on FIGS. 10 and 11 of U.S. Pat. No. 5,580,530. Those skilledin the art will appreciate that a booster need not contain hydrogenperoxide and thus can be a dry booster, and that the adaptor describedhereinbelow can be used with the booster, whether or not the boostercontains an antimicrobial agent, e.g., hydrogen peroxide. Those skilledin the art will also appreciate that the booster and the adaptor can beparts of a single unit.

The adaptor 30 is shown in more detail in FIG. 3A herein. The adaptor 30includes a cylindrical tubular body 34, an inwardly facing annularflange 36 for firmly attaching the cylindrical tubular body 34 to thebooster 20, a truncated cone 38, the opening 32, and texturing 40 on thecontact surface of the truncated cone 38 surrounding the opening 32. Theadaptor has one or a combination of the following properties.

First, texturing can be added to the contact surface. The texturing cantake various forms such as ridges, concentric rings, uneven surfaces,projections having equal heights, projections with varying heights, etc.Whatever form of texturing is used, there can be a plurality of theridges, rings, or projections of equal or varying heights. The height ofthe texturing varies and is generally related to the viscosity of theantimicrobial or cleaning fluid. The height of the texture varies fromapproximately 0.0001 millimeters to approximately 50 millimeters. Theheight of the texture for an antimicrobial fluid which is a gas willgenerally be less than for an antimicrobial fluid which is a liquid,because a gas has a lower viscosity than a liquid. Although the heightof the texturing can be determined by one skilled in the art, ingeneral, a height of approximately 0.001 millimeters to approximately 5millimeters is preferred for an antimicrobial agent which is a gas. Theheight of the texturing for a gas is more preferably in the range ofapproximately 0.01 millimeters to approximately 2.0 millimeter, and mostpreferably in the range of approximately 0.1 millimeters toapproximately 1.0 millimeters. The height of the texturing which ispreferred for a liquid is normally in the range of approximately 0.01 toapproximately 5 millimeters, depending on the viscosity of the liquid.The height of the texturing for a liquid is more preferably in the rangeof approximately 0.1 millimeters to approximately 4 millimeters, andmost preferably in the range of approximately 0.2 to approximately 2millimeters.

The texturing preferably extends to the inside of the opening 32, sothat the area directly facing the lumen 50 as well as the outer surfaceof the truncated cone 38 surrounding the opening 32 is textured. Theportion of the truncated cone 38 which is textured is preferably in therange of approximately 0.001 to 50 millimeters, more preferably in therange of approximately 0.01 millimeters to approximately 20 millimeters,and most preferably in the range of approximately 0.1 millimeters toapproximately 10 millimeters, radically extending from the edge of theopening 32. The amount of the contact area to be covered with texturemay depend on the length of the occluded area. The total length of thetextured surface is preferably approximately 5 times the length of theoccluded area, more preferably approximately 3 times the length of theoccluded area, and most preferably approximately 1.5 times the length ofthe occluded area. The inwardly facing annular flange 36 fits into ashallow annular groove on the booster 20 when the adaptor 30 is fittedinto place on the booster, firmly attaching the adaptor 30 to thebooster 20. Those of skill in the art will appreciate that thedimensions of the truncated cone 38 and the opening 32 can be varied toaccommodate various types of instruments to be sterilized.

Second, the material, at least in the contact area, preferably iscompatible with the sterilant or sterilization agent, that is, hasminimum chemical and physical interaction with the sterilant orsterilizing agent. Chemical interaction includes chemical reaction orcatalytic decomposition of the sterilant. Physical interaction includesabsorption or adsorption of the sterilant by the material. Third, thematerial, at least in the contact area, can be permeable to thesterilant so that the antimicrobial fluid can penetrate through thematerial.

Suitable materials for fabricating the adaptor, at least in the contactarea, can include, but are not limited to, polyolefins (includingthermoplastic elastomers), fluorinated and/or chlorinated polyolefins(including thermoplastic elastomers), fluorovinylidene,chlorovinylidene, liquid crystal polymers such as wholly aromaticpolyester or polyester-amide, silicone rubber, fluorinated siliconerubber, or polyester. These materials can be mixed with one or morefillers which have minimum chemical/physical interactions with thechemical sterilant. Fillers can be added to enhance mechanical,electrical, or thermomechanical properties.

The following procedure may be used when sterilizing equipment with thebooster 20 and the adaptor 30. An appropriately sized adaptor 30 isselected for the particular lumen 50 or other equipment to besterilized. The adaptor 30 is attached to the booster 20, and the lumen50 or other instrument to be sterilized is inserted into the opening 32.The booster 20 is activated by puncturing the membrane wall, and thehydrogen peroxide or other sterilizing agent is free to enter theadaptor 30 and the interior of the lumen 50 or instrument. In generalpractice, the activated booster 20, adaptor 30, and lumen 50 are placedinto a sterilization chamber, the chamber is sealed, and the chamber isevacuated, preferably to a pressure of approximately 100 torr or less,more preferably to a pressure of approximately 50 torr or less, and mostpreferably to a pressure of approximately 10 torr or less. Anantimicrobial fluid is then injected into the chamber, where itvaporizes and contacts the exposed surface of the equipment. Forexample, in the case of a lumen, it will be apparent from the foregoingto those skilled in the art that the lumen may be sterilized by thepassage of antimicrobial vapor or gas from the chamber and through thelumen, and/or by the passage from a booster attached to the lumen,through the lumen and into the chamber, depending on the respectivepressures in the booster and chamber. In either case, sterilization inthe contact area takes place. Various factors known to those skilled inthe art can be used to enhance sterilization such as heat, plasma, orhigh frequency radiation.

The hydrogen peroxide or other antimicrobial fluid in the booster 20volatilizes when the chamber is evacuated. The germicide vapor entersthe adaptor 30 and the lumen 50, sterilizing the interior of the lumen.The exterior of the lumen is sterilized by the antimicrobial agent whichis injected into the chamber.

FIGS. 3A and 3B illustrate the use of the adaptor 30 with a lumen 50.One skilled in the art can appreciate that the size of the opening 32 onthe adaptor 30 can be varied, depending on the size of the lumen 50 orother equipment connected to the adaptor 30. The body of the adaptor 30can have shapes other than a cylinder, depending on the shape of thebooster 20. For example, a rectangular adaptor 30 would be used if thebooster 20 were rectangular. Similar modifications would be obvious tothose skilled in the art.

The adaptor 30 can have several features which make the sterilization ofthe lumen 50 even more effective than previous devices. Some of thesefeatures are illustrated in FIG. 4, which is a blowup of FIG. 3B,showing the area of contact between the lumen 50 and the adaptor 30.First, the areas of contact between the adaptor 30 and the lumen 50 orother medical device can be reduced by using textured surfaces on theadaptor 30. Thus, the opening 32 and the part of the truncated cone 38which contact the lumen 50 can be textured, as shown in FIG. 4. Only thetips of the texturing devices remain as areas of contact between theadaptor 30 and the lumen 50. The contact area is far less than if thetexturing were not present. In addition, there are small gaps betweenthe ridges or “bumps” of the texturing which create an uneven surface.The uneven surface allows fluid penetration in both longitudinal andtransverse directions. Therefore, the antimicrobial agent, rinsingfluid, or cleaning fluid can enter these gaps and reach areas whichwould otherwise be inaccessible.

Finally, if the material used to construct the adaptor 30 is permeableto the antimicrobial agent, typically hydrogen peroxide, peracetic acid,or chlorine dioxide, further enhancement of the sterilizationeffectiveness can be achieved. The antimicrobial agent can penetrate theadaptor 30 to reach any areas of contact between the adaptor 30 and thelumen 50 or other instrument which remain after the contact areas areminimized through surface texturing. FIG. 4 shows arrows illustratingthe penetration of the sterilant vapor to the contact areas both throughthe gaps between the unevenness of the texturing and through thepermeable material from which the adaptor 30 can be fabricated.

The effectiveness of penetration of the antimicrobial agent through thematerial of the adaptor 30 to the contact areas can be even furtherenhanced by making the adaptor 30 thinner in the contact areas than inthe remainder of the adaptor 30. For example, in FIGS. 3A and 4, thewall thickness of the truncated cone 38 of the adaptor 30 decreases fromthe outer end 42 to the opening 32. The portion of the truncated cone 38which is in contact with the lumen 50 is the thinnest part of thetruncated cone 38, and the antimicrobial agent can penetrate to thecontact area between the adaptor 30 and the lumen 50 more effectivelythan if the adaptor 30 in this area were thicker. Making the adaptor 30thinner in the contact areas than in the remainder of the adaptor 30 isa way to further enhance the penetration of the antimicrobial agentthrough the material of the adaptor 30 into the contact area. Althoughthis is a preferred embodiment, it is not a required feature.

By using one or a combination of these features in the adaptor 30, thecontact area can be adapted so that the antimicrobial agent canpenetrate the areas of contact between the adaptor 30 and the lumen 50more effectively than in previous designs. These features include:applying texture or uneven surfaces to the contact area so as to reducesurface contact and enhance bidirectional diffusion of sterilant; usinga material which has minimal chemical and physical interaction with thesterilant; and forming the adaptor 30 from a material that is permeableto the sterilant so that the sterilizing agent can penetrate thematerial.

The embodiments of the method and the apparatus of the present inventioncan be used whenever there are areas of contact between an article to besterilized through sterilization and a connecting device for thearticle. Often, the connecting device will have an aperture throughwhich the article is inserted. Those skilled in the art will appreciatethat the various adaptors described herein are examples of connectingdevices. There are areas of contact between the aperture of theconnecting device and the article to be sterilized. The article to besterilized can include a lumen, rod, or other device. The methods of thepresent invention can be used in the connecting device and/or thearticle to be sterilized. These methods include the use of texturing onthe areas of the connecting device which contact the device to besterilized in order to reduce the contact area between the article andthe connecting device. Second, the connecting device can be made of amaterial which is permeable to the antimicrobial agent so that anyremaining contact surfaces can be sterilized by penetration of theantimicrobial agent through the material of the adaptor. Those skilledin the art are aware that silicone is one of the polymers which is mostpermeable to gases and vapors. Third, the selected material can be amaterial which has minimal physical and chemical interaction with theantimicrobial agent. Ways to optimize these design modifications will beapparent to those skilled in the art. Generally, the height of thetexturing is selected to match the viscosity of the sterilant orsterilizing agent so that more sterilant or cleaning fluid flows aroundthe texturing than through the material of the adaptor, connector, ordevice. The embodiments of the method and the apparatus are applicableto sterilization, rinsing, disinfection, and cleaning of devices withcontact areas.

Embodiments of the method and the apparatus of the present invention canalso be used to enhance the penetration of antimicrobial agents,disinfection fluids, rinsing fluids, or cleaning fluids to contact areaswithin a medical device during cleaning, rinsing, disinfecting, andsterilization processes. The embodiments of the method and the apparatushave broad applicability.

Often a medical device is made of two or more pieces. There are likelyto be contact areas between the pieces from which the medical device isformed. FIG. 5 shows one example of a medical device made up of two ormore pieces and having contact areas, a pair of scissors 60. The pair ofscissors 60 is made up of two cutting blades 64 joined at the center bya pin 68 which forms a pivot point. The portion of the cutting blades 64in the area of the pin 68 form a contact area which is difficult toclean, disinfect, rinse, or sterilize.

FIG. 6A shows a cross section of the two blades 64 and the pin 68 of thescissors 60 of FIG. 5, where the pair of scissors 60 is in a closedposition. In the embodiment shown in FIG. 6A, a plurality of grooves 70are present in the contact area around the pin 68 in one of the blades64. The grooves 70 allow cleaning fluid, disinfecting fluid, rinsingfluid, or germicide to flow into the contact area, cleaning,disinfecting, rinsing, or sterilizing the contact area. FIG. 6B showsthe two blades 64 of the scissors 60 in an open position. The contactarea between the two blades 64 when the pair of scissors 60 is in theopen position shown in FIG. 6B is less than the contact area between thetwo blades 64 when the scissors 60 are in the closed position, as shownin FIG. 6A. The grooves 70 allow cleaning fluid, disinfectant, rinsingfluid, or sterilant to flow into the contact areas, whether the pair ofscissors 60 is in the open position or in the closed position. Becausethe contact area of the pair of scissors 60 is reduced when the pair isscissors 60 is in the open position, it is preferred that the cleaning,disinfecting, rinsing, or sterilizing be performed when the pair ofscissors 60 is in the open position, though the grooves 70 or othertexturing devices in the contact area increase the effectiveness of thecleaning, disinfecting, rinsing, or sterilizing whether the pair ofscissors 60 is in the open position or in the closed position.

FIG. 8A shows a cross section of an embodiment of the scissors 60 ofFIG. 7 in which both blades 64 making up the scissors 60 have aplurality of grooves 70 in the contact area in the region of the pin 68which joins the two blades 64 at a pivot point. In FIG. 8A, the scissors60 are in a closed position. FIG. 8B shows a cross section of thescissors 60 of FIG. 7 in an open position. The amount of contact areabetween the blades 64 in the open position shown in FIG. 8B is reducedfrom the contact area between the blades 64 in the closed position shownin FIG. 8A. Cleaning fluid, disinfectant, rinsing fluid, or germicidecan flow through the grooves 70 into the contact area, cleaning,disinfecting, rinsing, or sterilizing the remaining contact area.

In the embodiment shown in FIG. 8A, the grooves 70 in the two blades 64are in a staggered arrangement, that is, a point 72 of the groove 70 inan upper blade 64 is aligned with a valley 74 in a lower blade 64. Asseen in FIG. 8A, there are no points of contact between the top blade 64and the bottom blade 64 in the portion of blades 64 with grooves 70 whenthe blades 64 are in the closed position in the embodiment where thegrooves 70 in the two blades 64 are in a staggered arrangement.

FIGS. 8C and 8D show an alternate embodiment of the scissors 60 in whichthe points 72 in the upper blade 64 are aligned with the points 72 inthe lower blade 64, and the valleys 74 in the upper blade 64 are alignedwith the valleys 74 in the lower blade 64.

FIGS. 9 and 10 show two alternative perspective views of the blades 64of the embodiments shown in FIGS. 8C and 8D. The points 72 of thegrooves 70 in a the top blade 70 are aligned with the points 72 of thegrooves 70 in the bottom blade 70. In the closed position shown in FIG.9, the contact areas between the two blades 64 are a plurality ofparallel lines formed by the contact between the points 72 in the upperblade 64 and the points 72 in the lower blade 64.

FIG. 10 shows the two blades 64 in an open position. When the blades 64are in the open position shown in FIG. 10, the areas of contact betweenthe points 72 of the grooves 70 in the top blade 64 and the points 72 ofthe grooves 70 on the lower blade 64 are a plurality of points. Thegrooves 70 on the blades 64 thus greatly reduce the amount of contactarea between the two blades 64, whether the blades 64 are in an openposition or in a closed position. Because the contact areas between theblades 64 are a plurality of points when the blades 64 are in an openposition versus a series of lines when the blades 64 are in a closedposition, it is preferred that the blades 64 be in an open position whenthe cleaning, disinfecting, rinsing, or sterilization is performed.Regardless of whether the blades 64 are in an open position or in aclosed position, cleaning fluid, rinsing fluid, disinfectant, orgermicide can flow through the grooves 70 to clean, rinse, disinfect, orsterilize the blades 64, even the contact areas between the blades 64.

FIGS. 12A, 12B, and 12C show various embodiments of texturing that maybe used to reduce the contact area between two or more parts of amedical device, for example the pair of scissors 60 shown in FIG. 11. Inthe embodiment shown in FIG. 12A, the texturing on the contact surfaceis in the form of a plurality of projections 78 in random positions onthe contact surface. In the embodiment shown in FIG. 12B, the texturingon the contact surface is in the form of projections 78 aligned inregular rows on the contact surface. In the embodiment shown in FIG.12C, the texturing on the contact surface is in the form of grooves 70.Although the projections 78 and grooves 70 of FIGS. 12A, 12B, and 12Care shown as having equal heights, in other embodiments, the projections78 and grooves 70 can have unequal heights. Other forms of texturing onthe contact surfaces are suitable for use in the embodiments of theapparatus and the method of the invention, and the embodiments oftexturing shown in FIGS. 12A, 12B and 12C are not meant to be limiting.

In other embodiments, the plurality of projections 78 can have theshapes of points, lines, or a combination of points and lines. In someembodiments, the plurality of projections 78 can be combinations of therandom arrangement of projections 78 of FIG. 12A, the arrangement ofprojections 78 in rows of FIG. 12B, and/or the grooves 70 of FIG. 12C.

The plurality of projections or texturing on the contact areas betweenthe two or more parts surfaces provide a pathway for the cleaning fluid,rinsing fluid, scrubbing fluid, or germicide to contact the contactsurfaces. The projections 78 are adapted so that when fluid is appliedto the medical device, more fluid flows around the projections ortexturing than through the material of which the medical device is made.The fluids can be liquid, vapor, or gas.

When medical devices are made of two or more parts with contact areasbetween the parts, the parts are often movable. As shown in the exampleof the scissors 60 of FIGS. 5, 7, and 11, the two parts are oftenmovable around a pivot. The pivot in the example of the scissors 60 ofFIGS. 5, 7, and 11 is the pin 68.

The medical device with two or more parts can be made from a variety ofmaterials such as metal or nonmetals, including, but not limited to,TEFLON™, a tradename for polytetrafluoroethylene, nylon, a generic namefor polyamide, polyolefins (including polyethylene, polypropylene, andthermoplastic elastomers), stainless steel, titanium alloy, aluminumalloy, nickel-chrome alloy, liquid crystal polymer, polyester, siliconrubbers, and styrenic thermoplastic, including thermoplastic elastomers.Further, the materials from which the two or more parts are formed neednot be the same. For example, one part of the medical device can be madeof metal and another part from a non-metal.

The medical device with two or more parts can be disposable or reusable.The contact areas on the medical device can be due to a joint, a hinge,a box lock, or a mated surface. Devices with hinged surfaces includescissors, forceps, and clips. Typical medical devices with two or moreparts having contact surfaces include scissors, forceps, holders,hemostats, or rongeurs. The embodiments of the apparatus and the methodof the present invention can also be applied to luer locks, connectorhousings, or any connectors that join two devices, for example, ventingcaps for flexible endoscopes or connectors on flexible endoscope headsfor all-channel irrigators.

Fluids which may be used with the embodiments of the apparatus and themethod of the invention include cleaning fluids, rinsing fluids,scrubbing fluids, or germicides. The germicide may be a liquid, a gas,or a vapor. The germicide can be a disinfectant or a sterilant.

One or more of the pieces forming the medical device can incorporate thefeatures of the embodiments of the method or the apparatus of thepresent invention to enhance the penetration of the fluid to the contactareas. These features include the use of texturing or uneven surfaces onone or more of the pieces forming the medical device in the contactareas between the two or more pieces. The texturing helps to reduce thecontact area. between the pieces forming the medical device. Second, oneor more of the pieces forming the medical device, at least in thecontact area, can be made of a material which is permeable to theantimicrobial agent. Third, the material selected to form one or more ofthe pieces forming the medical device, at least in the contact area, canbe a material which has minimal physical and chemical interaction withthe antimicrobial agent. Any one or a combination of these features canbe used to enhance the penetration of the cleaning fluid, rinsing fluid,scrubbing fluid, disinfecting fluid, or sterilizing fluid to the contactareas between the two or more pieces forming a medical device.

The antimicrobials used with the embodiments of the method and devicesof the various embodiments of the present invention include solutions ofglutaraldehyde, hydrogen peroxide, chlorine dioxide, peracetic acid, orother antimicrobials, either in a pure form or in an inert medium.Although high concentrations of the antimicrobial agents are moreeffective, material compatibility and handling problems may arise athigh concentrations.

When a medical device with two or more parts having embodiments of theapparatus of the present invention is cleaned, rinsed, scrubbed,disinfected, or sterilized with a liquid, the medical device iscontacted with the cleaning, rinsing, scrubbing, disinfecting, orsterilizing liquid. Advantageously, the medical device is contacted withthe liquid in a vessel. If the contacting is in a vessel, the liquid maybe circulated in the vessel. The cleaning, rinsing, scrubbing,disinfecting, or sterilizing liquid penetrates to the contact areas ofthe medical device. More liquid flows around the plurality ofprojections on the contact surface than through the material of themedical device, thus cleaning, rinsing, scrubbing, disinfecting, orsterilizing the medical device and the contact areas between the two ormore parts of the medical device. The effectiveness of the cleaning,rinsing, scrubbing, disinfecting, or sterilizing can be enhanced evenfurther by moving the two or more parts of the medical device during thecleaning, rinsing, scrubbing, disinfecting, or sterilizing. Moving theparts of the medical device changes the contact areas between the two ormore parts.

If the medical device with two or more parts having embodiments of theapparatus of the present invention is to be cleaned, rinsed, scrubbed,disinfected, or sterilized with a vapor or gas, the medical device isplaced in a chamber, the chamber is sealed, and the cleaning, rinsing,scrubbing, disinfecting, or sterilizing fluid is introduced into thechamber. The pressure in the chamber may optionally be reduced tovaporize the fluid. More fluid flows around the projections on thecontact area than flows though the material of the medical device toclean, rinse, scrub, disinfect, or sterilize the contact area betweenthe two or more parts of the medical device. Contacting the medicaldevice also cleans, rinses, scrubs, disinfects, or sterilizes theremainder of the medical device which does not have contact areas.

In a preferred embodiment, the method and device of the presentinvention relate to the sterilization of articles, such as medicaldevices containing long, narrow lumens, using a dry booster. The medicaldevices are devices such as endoscopes, catheters, tubing, or otherinstruments having lumens, where the device is preferably sterilizedbefore use. Typical applications include surgery, medical applications,and the agricultural and fermentation industries.

The preferred embodiment has particular advantage in applications forsterilizing lumens having internal diameters of 3 mm or less or having alength of 27 cm or more, though the method is also applicable to lumenshaving wider diameters or shorter lengths. The germicides used with themethod of the present invention are varied. Suitable germicides include,without limitation, glutaraldehyde, hydrogen peroxide, chlorine dioxide,or ethylene oxide. Unlike the other methods which use boosters, thegermicide is not limited to being liquid at atmospheric pressure and avapor at the temperature and pressure utilized in the sterilizationprocess. Both vapor and liquid processes are applicable to theembodiments of the present method utilizing a dry booster. With the useof the device of the present invention, antimicrobial vapor is drawnthrough the lumen or interior of the tube of the instrument during thevapor sterilization process without the need to supply a separate vialof liquid germicide on the end of the lumen, as with the wet boosterspreviously used.

The procedure for vapor sterilization using a dry booster is generallyas follows. The article to be sterilized is placed into thesterilization chamber, the chamber is sealed, and the chamber isevacuated to a pressure of less than about 50 torr, more preferably to20 torr or less. An antimicrobial solution is then injected into thechamber, where it vaporizes and contacts the exposed surfaces of thearticle. The time necessary for total kill of specific microbial agentsvaries with the type and concentration of antimicrobials present andwith the degree of exposure to the microbial agent. Microbials incracks, crevices, mating surfaces, or diffusion restricted areas aresomewhat protected from the antimicrobial agent and require more timefor total kill than microbials on the external surface of the article.Heat or high frequency radiation such as plasma may be used to increasethe effectiveness of the antimicrobial and its penetration into remoteareas of the instrument.

The device of the preferred embodiment comprises a vessel and a meansfor connecting the vessel directly to the lumen or the end of the tubeof the article to be sterilized. Unlike the prior vessels, the vessel ofthe dry booster of the present invention does not contain antimicrobialsolution. The prior boosters contained antimicrobial liquid whichvaporized when exposed to vacuum. The antimicrobial vapor traveled fromthe vessel into the lumen.

In the preferred embodiment, the vessel attached to the lumen does notcontain antimicrobial liquid. When the chamber is evacuated, the vessel,the lumen, and the means for connecting the vessel to the lumen are alsoat least partially evacuated. When antimicrobial vapor is injected intothe chamber, the antimicrobial vapor is drawn into the lumen because ofthe vacuum from the large evacuated volume of the vessel attached to thelumen. Those skilled in the art will appreciate that injection of theantimicrobial vapor is injected into the chamber causes the pressure inthe chamber to be higher than in the booster, thereby enhancing flow ofthe antimicrobial vapor from the chamber into the dry booster throughthe lumen. Unlike the prior boosters, the antimicrobial vapor is drawninward into the vessel from the sterilization chamber rather than beingdrawn out of the vessel into the sterilization chamber. Although in bothcases, the antimicrobial vapor is drawn through the lumen, with the drybooster of the present invention, there is no need to have a vesselcontaining antimicrobial liquid. Those skilled in the art willappreciate that the pressure in the chamber can be reduced after theflowing of the antimicrobial vapor or gas from the chamber in the drybooster through the lumen (such as by venting the chamber to theatmosphere), causing at least a portion of the antimicrobial vapor orgas in the dry booster to flow from the dry booster through the lumenand into the chamber.

A form of “dry booster” suitable for use in the method of the presentinvention is shown in FIG. 13. A lumen 100 is attached by a first end toan adaptor 200. The second end of the lumen is open to the interior ofthe sterilization chamber. The adaptor 200 shown in FIG. 13 is describedin U.S. Pat. No. 5,580,530, herein incorporated by reference. Theadaptor is shown as item 170 in FIG. 6 of U.S. Pat. No. 5,580,530. Theadaptor 200 comprises a cylindrical tubular body 220 formed of a softthermoplastic elastomer, such as Schafer, GmbH THEKA-FLEX, S 2030M orsilicone. Those skilled in the art will appreciate that the use of thesematerials is not limited to the adaptor 200, and that other connectingdevices may also comprise these materials. For the adaptor 200 in FIG.13, a truncated cone 240 extends inwardly, proximally, from a distal end260 of the adaptor body and terminates in a central opening 280. Thelumen 100 is inserted into the central opening 280 of the adaptor 200.The end of the adaptor 200 not having the truncated cone 240 is attachedto a vial 300.

The vial 300 is a receptacle of any shape which encloses a substantialempty volume. Although the vial 300 of FIG. 13 is a cylinder, othershapes are suitable, including round, rectangular, square, elliptical,or any other suitable shape. All that is important is that the vial 300and the adaptor 200 enclose a substantial volume of space which can beevacuated when the vial 300 is attached to the adaptor 200 and the lumen100.

Other forms of adaptor 200 and vial 300 are suitable for use with themethod of the invention, including the various adaptors describedherein. For example, those skilled in the art are aware that silicone isone of the polymers which is most permeable to gases and vapors, andthus also realize that an antimicrobial gas or vapor can penetrate thecontact area between the adaptor and lumen when the adaptor, at least inthe contact area, comprises a material such as silicone. All that isnecessary is that the adaptor 200 provide a fluid link between the lumen100 and the vial 300 and that the vial 300 and adaptor 200 enclosesufficient volume relative to the volume of the lumen 100 to besterilized. As will be shown below, the required ratio of the volume ofthe vial 300 and adaptor 200 relative to the volume of the lumen 100depend on the process conditions in the sterilization. Some suitableforms of adaptor 200 and vial 300 for use in the method of the presentinvention are shown, for example, in FIGS. 1, 2, 2A, 3, and 3A of U.S.Pat. No. 5,580,530. The embodiments of the adaptor shown in U.S. Pat.No. 5,580,530 include an expandable sheath, a bushing comprising aseries of rings of inwardly extending plastic flaps, a bushing with anaperture for attaching disposable cartridges, a drawstring on a pouch,and a “zip-lock” closure on a pouch. These forms of the adaptor 200 areillustrative only, and the method of the invention is not limited tothese forms of adaptor 200.

The vial 300 can comprise any three dimensional container preferably ofsemi-rigid or rigid material, having an opening therein. The vial 300may be made of, e.g., polyethylene, polypropylene, glass, or any othermaterial which is compatible with the antimicrobial vapor. In theembodiments shown in FIGS. 3 and 3A of U.S. Pat. No. 5,580,530, the vial300 comprises a pouch. In the embodiments shown in FIGS. 1 and 2A ofU.S. Pat. No. 5,580,530, the vial 300 comprises a vial. Any shape ofvial 300 may be used in the method of the present invention. The majorrestriction on the vial 300 is that the vial 300 and adaptor 200together have a volume larger than the volume of the lumen 100. Thoseskilled in the art will appreciate that, when the adaptor 200 is notpresent, the vial 300 should have an internal volume that is greaterthan the internal volume of the lumen. The required ratio of the volumeof the vial 300 and adaptor 200 relative to the lumen 100 depend on theprocess conditions, and the required ratios will be described in theExamples below.

Experiments were performed to compare the sterilization efficiency withand without a dry booster. In both sets of experiments, a biologicalindicator of 1.6×10⁶ Bacillus stearothermophilus spores on a stainlesssteel wire was placed in the center of a stainless steel lumen 100. Forthe experiments in Example 1, both ends of the lumen 100 were left open.For the experiments with the dry booster in Example 2, the apparatusshown in FIG. 13 was used. A first end of the lumen 100 was attached toa first end of the adaptor 200 described in FIG. 6 of U.S. Pat. No.5,580,530. The second end of the adaptor 200 was attached to an emptypolyethylene scintillation vial 300 with 17 mm outside diameter. Vials300 having varying lengths were tested to provide a range of volumes ofadaptor 200 and vial 300 relative to the volume of the lumen 100. Thesterilization results for the lumen without the dry booster are given inExample 1. The sterilization results for the experiments when the drybooster was attached to the lumen are given in Example 2.

Example 1 Sterilization Results with No Dry Booster on the Lumen

In Example 1, biological indicators of 1.6×10⁶ B. stearothermophilusspores were placed in the center of lumens of various lengths. Thelumens were placed in a 72.5-liter STERRAD 50 sterilizer with a standardSTERRAD 50 load double wrapped with CSR wraps. The chamber was evacuatedto 0.4 torr, and 740 mg of 59 weight % hydrogen peroxide were injectedfor 5 minutes to provide 6 mg/L of hydrogen peroxide vapor in thechamber. After 5 minutes of injection and diffusion, the chamber wasvented to atmospheric pressure, the lumens were removed, and thesterility results of the biological indicators were determined. Theresults are shown in Table 1 below.

TABLE 1 Sterility Results From Tests with No Dry Booster (No. ofPositives/No. of Samples) Lumen Size Sterility Results 1 mm × 250 mm 0/31 mm × 300 mm 0/3 1 mm × 350 mm 0/3 1 mm × 400 mm 1/2 1 mm × 450 mm 3/31 mm × 500 mm 2/2

As shown by the results in Table 1 above, under the test conditions, theinteriors of the 1 mm ID lumens longer than 350 mm were not sterilizedby exposure to hydrogen peroxide vapor.

In Example 2, a “dry booster” comprising an adaptor 200 and a vial 300containing no liquid sterilant was attached to one end of the lumen 100.All of the other test conditions were the same as in Example 1. Theresults in Example 2 demonstrate the improvement in sterilizationefficiency of the interiors of long lumens when the “dry booster”according to an embodiment of the method of the present invention wasattached to the end of the lumen 100 to be sterilized.

Example 2 Sterilization of Lumens With A “Dry Booster”

In the experiments of Example 2, one end of an adaptor 200 as describedin U.S. Pat. No. 5,580,530 was attached to an end of a 1 mm×400 mmstainless steel lumen to be sterilized. A biological indicator asdescribed in Example 1 was placed in the center of each lumen. Thesecond end of the adaptor 200 was attached to a 17 mm ID polyethylenescintillation vial 300 having varying lengths and therefore varyingvolumes, as shown in FIG. 13. The lumens 100 with the attached boosterscomprising an adaptor 200 and vial 300 were exposed to hydrogen peroxidevapor under the conditions described in Example 1, the chamber wasvented, and the sterility tests were measured. The results are shown inTable 2 below.

TABLE 2 Sterility Results From Tests with a Dry Booster (No. ofPositives/No. of Samples) Ratio of Dry Booster Volume/Internal Volume of1 mm × 400 mm Lumen Sterility Results 20:1 0/3 15:1 0/3 14:1 0/3 13:10/3 12:1 0/3 11:1 1/3 10:1 1/3  5:1 1/2

A 1 mm×400 mm stainless steel lumen was chosen for the tests in Example2, because the 400 mm lumen was the shortest lumen which was notsterilized without the need for a dry booster in Example 1.

There are two conclusions which can be drawn from the results shown inTable 2. First, use of a “dry booster” can enhance the sterilization ofthe interior of lumens. The interior of the 1×400 mm lumen in Example 1was not sterilized. By contrast, the interior of the 1×400 mm lumen wassterilized in the majority of the examples shown in Example 2, where adry booster was attached to the end of the 1×400 mm lumen.

Second, the interior of the 1×400 mm lumen was not sterilized unless theratio of the dry booster volume (the volume of the adaptor 20 and thevial 30) was at least 12 times as large as the internal volume of the 1mm×400 mm stainless steel lumen. In cases where the ratio of the volumewas less than 12:1, not all of the samples were sterilized. A volume ofdry booster to the volume of the lumen of 12:1 or more is thereforerequired for the dry booster to be effective in enhancing thesterilization of the interior of the lumen, under the conditions ofExample 2.

The comparative results from Examples 1 and 2 demonstrate theimprovement in sterilization efficiency for long lumens when a drybooster having a volume of 12 or more times the volume of the lumen isattached to the end of the lumen to be sterilized and the chamber wasevacuated to a pressure of 0.4 torr before the hydrogen peroxide wasinjected into the chamber.

A series of experiments were performed to determine the sterilizationefficiency at various initial vacuum pressures. The length of time forwhich the vacuum was maintained before injection of the hydrogenperoxide was also varied. The effects of pressure and length of theevacuation time are shown in Example 3 below.

Example 3 Effects of Varying Evacuation Pressure and Evacuation Time

A plurality of 1 mm×500 mm stainless steel lumens 100, each containing abiological indicator, were placed in a 72.5 liter sterilization chamberas in Example 1. Dry boosters having various volumes were attached tothe ends of certain of the lumens, as shown in FIG. 13. The remainder ofthe lumens were placed into the chamber without a dry booster. Thechamber was evacuated to a pressure of either 0.4 torr or 0.1 torr andwas maintained at the pressure of 0.4 torr or 0.1 torr for a time periodof between 0 and 20 minutes, as noted in Table 3 below. A total of 740mg of 59 weight % hydrogen peroxide was injected for 5 minutes toprovide 6 mg/L of hydrogen peroxide vapor in the chamber. After 5minutes of injection and diffusion, the chamber was vented toatmospheric pressure, the lumens were removed, and the sterility resultsof the biological indicators were determined. The results are shown inTable 3 below.

TABLE 3 Dependence of Sterility Results on Evacuation Pressure,Evacuation Time, Presence of a Dry Booster, and Volume Ratio of DryBooster to Lumen (No. of Positives/No. of Samples) Sterility ResultsVolume Ratio of Evacuation Conditions Dry Booster Evacuation No to LumenPressure Evacuation Time Booster 10:1 5:1 3:1 0.4 torr 0 minutes 2/2 1/22/2 — 0.4 torr 5 minutes 2/2 0/2 2/2 — 0.1 torr 0 minutes 2/2 0/2 2/2 —0.1 torr 10 minutes  2/2 0/2 1/2 2/2 0.1 torr 20 minutes  1/2 — 0/2 0/2

There are several conclusions that can be drawn from the data in Table3. First, the sterilization efficiency of the lumen improves with lowerevacuation pressures and longer evacuation times. For example,sterilization with a 10:1 booster was not effective at 0.4 torr with novacuum hold time. The sterilization was effective when the vacuum wasmaintained at a pressure of 0.4 torr for 5 minutes, however. Similarly,sterilization with a 10:1 booster was not effective with a sterilizationpressure of 0.4 torr with no hold time, but the sterilization waseffective at a pressure of 0.1 torr with no hold time.

Second, the sterilization efficiency with a dry booster was at least ashigh as with no dry booster in all cases.

Third, the sterilization efficiency improved with higher ratios of drybooster volume: lumen volume. All but 1 of the coupons were sterilizedwhen a dry booster with 10 times the volume of the lumen was used. Thesterilization efficiency steadily decreased as the ratio of the drybooster volume to the volume of the lumen decreased from a ratio of 10:1to 5:1 and even further when the ratio decreased to 3:1.

Fourth, the ratio of the volume of the dry booster to volume of thelumen required to sterilize the interior of the lumen can be decreasedby using lower evacuation pressures and longer evacuation times. InExample 2, ratios of dry booster volume/lumen volume of 12:1 wererequired to sterilize the interior of the lumens with evacuationpressures of 0.4 torr with no hold on the evacuation time.

In Example 3, the interior of the lumens could be sterilized when thevolume of the dry booster (adaptor and vial):volume of lumen was 5:1 oreven 3:1 when the pressure was reduced to 0.1 torr and the chamber wasevacuated to 0.1 torr for 20 minutes. Evacuating the chamber to lowerpressures for longer times therefore allows dry boosters with lowervolumes relative to the volume of the lumen to be effective insterilizing the lumens.

It is believed that the reason that the sterilization efficiencyimproves with longer evacuation times is because the increased exposuretime to the vacuum removes more moisture from the lumen. When lessmoisture is present, more hydrogen peroxide can be drawn into the drybooster through the lumen.

In Example 4 below, a 1 mm×2000 mm TEFLON™ lumen was used rather thanthe 1 mm×500 mm stainless steel lumen of Example 3. The dependence ofsterilization efficiency with evacuation pressure and evacuation timewas studied.

EXAMPLE 4 Dependence of Sterility Results on Evacuation Pressure,Evacuation Time, Presence of a Dry Booster, and Volume Ratio of DryBooster to Lumen With a TEFLON ™ Lumen (No. of Positives/No. of Samples)Sterility Results Volume Ratio of Evacuation Conditions Dry BoosterEvacuation No to Lumen Pressure Evacuation Time Booster 3:1 2:1 1:1 0.4torr  0 minutes 3/3 0/3 1/3 — 0.1 torr 20 minutes 1/2 0/2 0/2 2/2

Even with a dry booster volume:lumen volume of 3:1, all of thebiological indicators in the 1 mm×2000 mm TEFLON™ lumens were sterilizedwith evacuation pressures of 0.4 and 0.1 torr. By contrast, when a 1mm×500 mm stainless steel lumen was sterilized in Example 3, not all ofthe biological indicators were sterilized even with dry booster having avolume 5 times larger than the lumen. The stainless steel lumen wasshorter than the TEFLON™ lumen, and the dry booster in the stainlesssteel lumen experiments had a higher volume relative to the volume ofthe lumen. Both the shorter length of the stainless steel lumen and thelarger volume of the dry booster in the experiments in Example 2 shouldhave improved the sterilization efficiency. Instead, the sterilizationefficiency with the longer TEFLON™ lumen and the smaller dry booster ofExample 4 was higher than with the stainless steel lumen in Example 3.

Further, when the chamber was evacuated to 0.1 torr for 20 minutes,sterilization of the TEFLON™ lumen was effective even when the ratio ofthe volume of the dry booster (adaptor 20 and vial 30) relative to thelumen 10 was as low as 2:1.

It is believed that the improved sterilization efficiency with theTEFLON™ lumen in Example 4 is due to the TEFLON™ lumen being lessreactive with the hydrogen peroxide vapor. The comparative results ofExamples 3 and 4 demonstrate that TEFLON™ lumens are easier to sterilizethan stainless steel lumens.

The results of Examples 1-4 demonstrate that use of the “dry booster”can enhance the sterilization of the interior of lumens. Further, theratio of the volume of the “dry booster” relative to the volume of thelumen required for sterilization of the interior of the lumen variesdepending on the process conditions and the type of lumen to besterilized. A volume ratio of 12:1 was required with evacuationpressures of 0.4 torr with no hold time with a stainless steel lumen, asshown in Example 2. When the pressure was reduced to 0.1 torr and theevacuation time was increased to 20 minutes, a volume ratio of 3:1 wasrequired, as shown in Example 3. Sterilization of a TEFLON™ lumen at 0.1torr and 20 minutes evacuation time was effective with a dry boostervolume:lumen volume of 2:1, as shown in Example 4. The sterilizationefficiency with a “dry booster” therefore depends on both the processconditions and the type of lumen to be sterilized. Plasma may optionallybe introduced to enhance the sterilization.

FIG. 14 shows an alternative form of the “dry booster” with someenhancements over the “dry booster” of FIG. 13. The “dry booster” ofFIG. 14 comprises an adaptor 200 and a vial 300 as does the “drybooster” of FIG. 13. The “dry booster” shown in FIG. 14 additionallycomprises a flow restrictor 400 between the adaptor 200 and the vial300. The flow restrictor 400 limits the flow of the antimicrobial vaporthrough the lumen 100, helping to maintain the pressure differencebetween the vial 300 and the lumen 100.

Further, the “dry booster” shown in FIG. 14 further comprises a checkvalve 500 on the vial 300. The check valve 500 allows the gas inside thevial 300 to be released from the vial 400 directly into thesterilization chamber rather than having to be evacuated through thelumen 100. The check valve 500 therefore reduces the length of timerequired to evacuate the vial 300.

The embodiments of the dry booster and the methods of sterilizingdevices with the embodiments of the dry booster provide enhanced methodsof sterilizing the interior of lumens without the need to attachboosters containing antimicrobial solutions.

The enhanced sterilization efficiency with the dry booster is probablydue to the internal volume of the dry booster and the initial pressuredifference between the inside and outside of the dry booster. The volumeand the pressure act as a driving force to cause the flow of germicideinto the booster through the lumen. The dry booster can also be appliedto a liquid phase process or a process at a pressure higher thanatmospheric pressure by creating a higher pressure outside the boosterthan inside the booster. The amount of germicide flow into the boostercan be controlled by the volume of the booster. The liquid, gas, orvapor process can be enhanced by reducing the pressure in the boosterand the lumen before introducing the germicide.

Another aspect of the invention involves a system for sterilizing alumen, where the system includes a vacuum chamber, a pump to evacuatethe chamber, a dry booster, where the dry booster is attachable to anddetachable from the lumen, and a source of germicide. Preferably, thedry booster comprises an adaptor that contacts the lumen in a contactarea. Preferably, the dry booster encloses an internal volume that isgreater than the internal volume of the lumen. More preferably, theinternal volume of the dry booster is at least 2 times the volume of thelumen.

Various modifications and alterations of this invention will be apparentto those skilled in the art without departing from the scope and spiritof this invention. It should be understood that the invention is notlimited to the embodiments disclosed therein, and that the claims shouldbe interpreted as broadly as the prior art allows.

1. An apparatus for sterilizing a lumen, comprising a booster and aconnecting device between the booster and the lumen, wherein theconnecting device comprises a silicone material.
 2. The apparatus ofclaim 1, wherein the connecting device comprises textured or unevensurfaces.
 3. The apparatus of claim 1, wherein the booster comprises avessel containing an antimicrobial fluid.
 4. The apparatus of claim 1,wherein the booster is a dry booster.
 5. An apparatus for sterilizing alumen, comprising a dry booster and a connecting device between the drybooster and the lumen, wherein the lumen contacts the connecting deviceat a contact area and wherein the contact area is adapted to enhancepenetration of an antimicrobial vapor or gas to the contact area.
 6. Theapparatus of claim 5, wherein the connecting device is constructed froma material, at least in the contact area, that is permeable to theantimicrobial vapor or gas.
 7. The apparatus of claim 5, wherein thesurface of the connecting device in the contact area is textured oruneven.
 8. The apparatus of claim 5, wherein the dry booster encloses aninternal volume that is greater than the internal volume of the lumen.9. The apparatus of claim 5, wherein the dry booster comprises a flowrestrictor.
 10. The apparatus of claim 5, wherein the dry boostercomprises a check valve. 11-24. (canceled)
 25. An apparatus forsterilizing a lumen, comprising a booster and a connecting devicebetween the booster and the lumen, wherein the lumen contacts theconnecting device at a contact area and wherein the connecting devicecomprises an uneven or textured surface in the contact area.
 26. Theapparatus of claim 25, wherein the connecting device is constructed froma material, at least in the contact area, that is permeable to theantimicrobial vapor or gas.
 27. The apparatus of claim 25, wherein thebooster comprises a vessel containing an antimicrobial fluid.
 28. Theapparatus of claim 25, wherein the booster is a dry booster.